Give it to us raw and wriggling

Star Trek fans know that Klingons prefer to eat their worms while they are still alive. It therefore seems fitting that biogerontologist’s favorite worm, C. elegans, in turn prefer their own food alive. Lenaerts et al. report that C. elegans has a nutritional requirement for some component of metabolically live microbes. This compound (or set of compounds) remains to be identified.

These findings may make it necessary to re-interpret a number of calorie restriction (CR) studies performed in axenic (bacteria-free) media — which deprives the worm of this required factor. Thus worms in axenic media may be undergoing not only CR but nutritional deficiency. If the required compound is diffusible, it might also go some way toward explaining why olfactory cues can influence health and lifespan. (The authors demonstrate that the component in question is probably not even soluble, but then again, many odorants aren’t.)